code: def _compute_over(self, B, A):
      assert A.ndim == B.ndim == 2
      assert A.shape[1] == B.shape[1] == 4
      A_w = A[:, 3:]  # * 1
      B_w = B[:, 3:] * (1 - A_w)
      C = A.copy()
      C[:, :3] *= A_w
      C[:, :3] += B[:, :3] * B_w
      C[:, 3:] += B_w
      C[:, :3] /= C[:, 3:]
      return np.clip(C, 0, 1, out=C)
  
file_path: mne-python/mne/viz/_3d_overlay.py
imports: from collections import OrderedDict
  import numpy
  from ..utils import logger
label_desc: Use image node_id 3 for calling the _LayeredMesh obj's underlying member method code with example usage: obj._compute_over(B, A) and returns: np